When Aphids Come Out (And What To Do About It)

Aphids are a likely culprit if you are having issues in your garden or with your flowers. Because they are such a common pest, knowing when to expect aphids can help you stay ahead of any problems. 

Aphids come out during the spring when the weather warms up and can be seen during the early or later part of the day. If you have aphids using a water treatment, insecticide soap, and encouraging natural predators like ladybugs, lacewings, and praying mantis will help protect your plants.

Identifying and correctly treating your plants can be a tricky process, but here is all the information you need to make sure you are staying ahead!

How To Know You Have Aphids

Aphids are one of the more common insects you might find in your garden or on your landscaping plants!

Because they are so common any time you have plants that are less than healthy, aphids are an automatic suspect. But how can you be sure that you have aphids and not some other common garden criminal? 

Signs On Your plants

One of the first signs of aphids is shiny, sticky leaves. Because sucking insects like aphids collect their nutrients directly from the plants in the form of liquid, they excrete sugary waste and excess moisture from the sap. 

This liquid collects and is called honeydew. Honeydew will be a thick, sticky liquid collecting on your plant’s leaves or on the stems and ground under where the insects are feeding.

Unlike actual honey, you shouldn’t be excited to see honeydew. 

How To Know You Have Honeydew

If the leaves on your plants suddenly turn black or brown, start twisting or curling, and you are seeing deformed new growth, these can all be signs of alarm. 

A quick glance might convince you that your plants are dying because of a herbicide drift or disease, and while that is always a concern, it might not be the case. 

The dark brown or black might be mold that has collected on the honeydew being left by the messy aphids. 

What Is Sooty Mold

This dark mold is called sooty mold and while it doesn’t infect the plants directly, it can cause stress and stunt the plants. This dark covering can also prevent sunlight from reaching the leaves, hindering growth. 

Even if you missed the signs of honeydew on your leaves, you won’t miss the dark mold that will cover your plant’s leaves and can quickly take action to combat your aphid infestation!

What Do Aphids Look Like On Your Plants?

There are other insects besides aphids that produce honeydew. Insects such as planthoppers, leafhoppers, whiteflies, psyllids, and mealybugs all produce honeydew and can lead to confusion on which pest is bugging your plants.  

To make sure that you are combating the correct insect, you’ll need to know what insect you are dealing with.

Aphids can be in a multitude of colors, including brown, black, gray, and more colorful green, yellow, or red. They are small, staying 1/16 to 1/8 an inch with a soft body and long legs. To further confuse identifying aphids, they can have wings or be wingless. 

Aphid Life Cycle 

Because the aphids can reproduce asexually, the females do not need a male aphid to lay eggs. Aphids will lay eggs in winter that hatch when it warms up.

In the spring, the newly hatched females will hold the eggs in their bodies and give live birth, which will shorten the reproduction cycle and allow up to 15 generations of aphids to be born in a season. 

Leading to a fast infestation on your vulnerable new growth. 

How Long Do Aphids Hang Around?

Their lifespan is around one month long and they can start producing nymphs. Nymphs are young aphids less than a week after hatching. 

Once the population reaches a certain point, the winged forms are birthed to spread to other plants and are called spring migrants. 

When the days shorten in late summer, wingless males and females are birthed so that they will fertilize eggs to survive the winter. 

Female aphids will take cover in plant debris or in heavy bark to spend the winter. 

How Aphids Attract Other Insects

One other sign of an aphid infection can be ants. Because the honeydew is an important ant food source, ants will start collecting honeydew when aphids are present. 

The ants will milk the aphids, earning them the nickname ant cows, stroking them for honeydew, to collect the sugary substance. The attentive ants will go so far as to carry the aphids to new plants once their food source is used up. 

Ants will protect the aphids and defend them from harm and other insects or build a shelter for the aphids. They sometimes bring root-dwelling aphids into their own nests. 

When Do Aphids Appear?

While aphids can be present year-round in warmer southeastern or southwestern states, they are highly reactive to the season and will become dormant when the temperature drops. 

Watch your greenhouse all year round for the beginnings of an aphid infestation since it will stay nice and balmy all year around. 

What Season Will You See Aphids On Your Plants?

Most areas see aphids appearing in early spring as new growth is emerging. The soft new growth is the perfect food source for aphids, making it easy to get to the sap inside. 

As the temperature warms up, the wingless females that have wintered in plant debris will emerge and are called stem mothers. They will start giving birth to young.

One female aphid can produce 50-100 nymphs. Yikes!

Once the females start reproducing, you might see the first signs of aphid inhabitation on your plants as their numbers quickly swell.

Aphids Tend To Hide On The Underside Of Leaves

In order to stay ahead of an infestation, make sure to visually check your plants at least twice a week during the growing season. 

Aphids will hide along the underside of leaves and will group together in defense against predators during the night. 

During the day, aphids should be spread out on your plants working to consume as much organic matter and sap from the soft parts of the plant as they can. 

Once it gets chilly, you might not see aphids out and about except during the warmest part of the day. 

Egg clusters will be under the leaves where the stem and leaf meet. But the eggs are so small you might not notice the eggs without a lighted magnifying glass. 

Where Else To Look For Aphids On Your Plants

Also, check any new growth such as stem tips or if there are any breaks in the stem they will collect there. 

It’s important to check your plants for aphids not only for the physical damage they can cause, but because they can be plant vectors carrying viruses from one plant to the next. 

According to North Carolina State Agriculture and Life Sciences, aphids can carry over 150 different types of plant viruses. 

North Carolina State lists some of the common viruses that aphids might bring to your garden including cucumber mosaic, tomato spotted wilt, beet mosaic, cabbage black ring spot, carnation latent, cauliflower mosaic, cherry ring spot, cucumber mosaic, onion yellow dwarf, pea wilt, potato Y, and turnip yellow mosaic. 

Why Do You Have Aphids In The First Place?

You can bring aphids accidentally into your garden or beds when you purchase plants somewhere. Checking plants before you bring them home can diminish the chances of aphids hitching a ride home from your local nursery.

Sometimes keeping your new plants separate in a “quarantine area” can help control any aphid infestation that might be in too early of a stage to be detectable. 

There are also certain factors that can encourage aphids to your yard in their winged form. Wingless aphids will normally stay on the same plant their entire life, but the winged aphids will look for new, appealing plants.

Aphids Love Young Plant Growth

If you are constantly trimming or pruning your plants that will stimulate new growth which can draw aphids to your garden. All the new growth is a perfect soft food source for the aphids to access the plant sap. 

Another cause can be over-fertilizing, University Of California recommends using a slow-release fertilizer to prevent adding too much nitrogen. Having high levels of nitrogen causes plants to overproduce the soft, new plant growth aphids are so attracted to. 

Using natural fertilizers like compost will allow a slow release of nutrients or using a small amount of fertilizer at a time throughout the growing season will also help. 

Types of Plants  

There are a lot of host plants for aphids. Peppers, tomatoes, leafy greens, cabbage, kale, and basil as some of the more popular plants for aphids. There are a variety of fruits and vegetables that attract aphids.

Plant	Common Aphids
Peppers	Sweet Pepper Aphid
Tomatoes	Potato Aphid
Leafy Greens	Lettuce Aphid
Cabbage	Cabbage Aphid
Kale	Cabbage Aphid
Basil	Several Species

Aphids are also attracted to flowering plants, such as roses, zinnias, coreopsis, sunflowers, and dahlias. 

Plant	Common Aphids
Roses	Rose Aphid
Zinnias	Black Bean Aphid
Coreopsis	Root Aphid
Sunflower	Melon Aphid
Dahlias	Green Peach Aphid

Fruit trees are not without aphid problems as well. Some aphids attracted to fruit trees can get fruit sap from the trunk, limbs, and even the roots of your fruit tree. 

There are also plants you can add to your garden or bed that repel aphids and many other pests. 

Garlic is a great addition to your garden with its strong pungent smell, it discourages many pests and especially aphids.

Marigolds also have an overpowering odor, and just like garlic, they can help keep away aphids. The smell mostly comes from their leaves and keeps pests away and benefits all the surrounding plants. 

What Should You do When You Have Aphids? 

1. Use Water To Wash Aphids Away

Using a powerful stream of water can dislodge the aphids from your plants. Make sure to do this during the middle of the day so that the plants have time to dry before nightfall. 

Make sure to remove the honeydew as well as the insects themselves. Hit any under leaves with your stream of water where the next generation of eggs might be hiding. 

Using this method will also wash away any sooty mold that has appeared.

Don’t use a pressure washer which can damage your plant and vegetables. 

The majority of aphids are wingless, so once you wash them off of your plant they are unable to climb back up. Read more here about what happens to aphids when they don’t have plants.

This method might not work for the smaller-winged aphid population, but most of the time, the force of the water will damage the wings of the aphids. 

Because aphids are so easy to knock off during a rainy season, you might see fewer aphids and more aphids during a particularly dry season. 

2. Utilize Natural Aphid Predators 

The most effective method for controlling aphids in your garden is to encourage natural predators.

Ladybugs

Lady Bugs are the most common predator of aphids. Especially their larvae, which will keep an aphid population from establishing itself. 

With over 450 species of ladybugs in North America alone, it is easy to draw them to your yard if you make a few modifications. Stop using pesticides that kill the good insects, not just the bad ones. 

Make sure there is a water source available in your garden in the form of shallow water dishes. Having a water source will attract ladybugs, butterflies, and hummingbirds, all of which are pollinators and will help your garden and flowers thrive.

A great pollinator watering system in place where insects can land and reach the water without it being too deep, something like this 2 Pack Bee Water Feeder, can increase good insects in your garden.  

Ladybugs or lady beetles can consume up to 65 aphids a day, and the larval can eat up to 23 aphids a day, according to the University of Minnesota Extension. It doesn’t take many ladybugs to protect your plants. 

Make Sure The Ladybugs Have Somewhere To Shelter 

If you are growing ground cover in your gardens such as clover or oregano it will allow the ladybugs to have somewhere to shelter at night when not on the aphid hunt. 

Ladybugs are available for purchase, but it can be extremely difficult to keep them alive until they can be released.

Make sure ladybugs have been refrigerated and keep them refrigerated until you are ready to release them. A lot of ladybugs are dehydrated and stressed, which leads to a low survival rate of purchased ladybugs. 

Release your ladybugs in the early morning or early evening when they are less likely to immediately leave your yard. 

Will The Ladybugs Hang Around?

After a few days, ladybugs will often relocate, warns the University of California. 95% of ladybugs will fly away within 48 hours. 

Because of the low retention rate and the need to continually release ladybugs as they leave and the aphids population builds backup, it is more effective to create a ladybug-friendly garden to attract them. 

Planting plants that are appealing to ladybugs will help draw a population of these helpful hunters.

Flowers in the Apiaceae, or the carrot, family will flower and attract ladybugs. Think about planting some of these helpful attractors, such as dill, fennel, cilantro, and Queen Anne’s lace. 

Plants in the aster or daisy family will draw ladybugs, including sunflowers, yarrow, and coneflower. Verbena flowers like lantana and lilac will also help bring ladybugs. 

Lacewings

The lacewing larvae are another natural predator for aphids and because they don’t sting or bite they are harmless to you. Lacewings come in a bright green or a brown and grow to about 3/4 an inch. 

Lacewings have four different life stages, starting with eggs, pupae, wingless larvae, and winged adults. Once a lacewing reaches the larvae stage, it can eat up to 200 aphids a week.

Attracting lacewings to your garden involves many of the same plants that draw ladybugs, including the carrot family, aster family, legumes, and verbena family. 

Lacewings vs. Ladybugs

One difference between the ladybug and lacewings is that it is much easier to purchase and release lacewings with more predictable results. 

The South Carolina Department of Natural Resources advises lacewing in their egg form, not the adult or larvae. They have a lifespan of about 30 days in their larvae form and during that time they’ll feed off of aphids. 

Once they are adults they need pollen, nectar, and even honeydew to survive. Because of the need for aphids in their diet, make sure you have a population of aphids before trying to introduce lacewings to your yard. 

Praying Mantis

The praying mantis can be just as likely to eat a honeybee as aphids, but they are unique and interesting insects that can help with aphid control.

You can purchase praying mantis eggs and release them into your garden if you are interested in having praying mantises in your yard. 

Reflective Material

One other method to prevent aphids from taking up residence on your plants is to prevent the winged form of aphids from coming into your garden or beds. 

Using reflective material such as reflective mulch or aluminum foil can disorientate the flying insect and keep them from landing on your plants. Try using Silver Metallic Plastic Mulch Sheets.  

If you don’t like the idea of having a shiny garden, try using aluminum pie plates around the base of your plants for a small reflective surface. These can also help bounce light onto your plants for additional sunlight. These inexpensive 9-Inch Disposable Aluminum Foil Pie Pans work well!

That’s A Wrap!

Aphids seek plants under stress that have cracks or sores on the stem and branches, keeping your plants well watered will keep them strong against the encroaching pest. 

Carefully monitoring your plants and watching for signs like the honeydew or damaged new growth can keep you ahead of a population swell and infestation of any aphids in your yard. 

You are most likely to find aphids are the connecting point of the stems and leaves connect or under the leaves. Also, check any damaged parts of the plant for aphids. 

Make sure to carefully check or quarantine any new plants coming into your yard to prevent introducing aphids yourself. 

Good luck defending your flowers and gardens from the pesky aphids!

References

Buga, S. V., and A. V. Stekolshchikov. “Aphids as pests of fruit-and berry-producing plants in Byelorussia.” Redia 92 (2009): 239.

Loxdale, Hugh D., et al. “The relative importance of short‐and long‐range movement of flying aphids.” Biological Reviews 68.2 (1993): 291-311.

Rocha, Elise A., et al. “Influence of urbanisation and garden plants on the diversity and abundance of aphids and their ladybird and hoverfly predators.” European Journal of Entomology 115 (2018): 140-149.